The relationships of serum α-synuclein, microtubule-associated protein 1 light chain 3, apolipoprotein A1 with cognitive function and disease progression in Parkinson's disease

Objective To detect the expressions of α-synuclein, microtubule-associated protein 1 light chain 3 (LC3) and apolipoprotein A1 (Apo A1) in serum of patients with Parkinson's disease (PD), and their correlations with cognitive function (CI) and disease progression.

Methods Ninety-six PD patients were selected as research group; another 90 healthy subjects were selected as control group. The patients were divided into CI group (42 cases) and cognitively normal group (54 cases) according to the Montreal Cognitive Assessment Scale (MoCA) score. PD patients were divided into stages Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅴ according to the Hoehn-Yahr (H-Y) Staging Scale, patients in stage Ⅰ to Ⅱ were included in early PD group (57 cases), and those with stage Ⅲ to Ⅴ were in middle and late PD group (39 cases). The levels of serum α-synuclein and LC3, PD and Apo A1 patients were determined. The correlations of α-synuclein, LC3, Apo A1 with H-Y staging were analyzed. Logistic regression analysis was applied to screen the influencing factors of occurrence of CI in PD patients.

Results Compared with the control group, the level of α-synuclein in the research group increased, and the levels of LC3 and Apo A1 decreased (P < 0.05); the level of α-synuclein in the early PD group was lower than that in the middle and late PD group, and the levels of LC3 and Apo A1 were higher than those in the middle and late PD group (P < 0.05); serum α-synuclein level was positively correlated with H-Y staging (P < 0.05). The area under the curve (AUC) of their combination to predict the occurrence of cognitive impairment in PD patients was 0.925, which was greater than prediction by α-synuclein, LC3, and Apo A1 alone (P < 0.05); α-synuclein, LC3, Apo A1, and history of hypertension were the influencing factors of CI in PD patients (P < 0.05).

Conclusion α-synuclein is highly expressed in the serum of patients with PD complicated with cognitive impairment, while the expression of LC3 and Apo A1 are low. The three are closely related to PD cognitive function and disease progression.